The present invention is directed to a novel oxygenate condensation catalyst and the process for the production of high molecular weight oxygenates from low molecular weight oxygenates by contact with this novel catalyst. In particular, the present invention relates to a novel solid catalyst composition and the process for using the catalyst to convert low molecular weight alcohols to higher molecular weight primary alcohols.
Numerous attempts have been made in the past to develop a commercially viable process for converting readily available lower alcohols to more valuable higher linear primary alcohols which are presently in great demand as commodity chemicals.
These attempts have generally been directed at developing the so-called Guerbet synthesis, a heterogeneous catalysis reaction whereby a primary or secondary alcohol containing a methylene group alpha to the carbinol moiety is condensed with itself or with a different alcohol also containing the methylene group to form a higher alcohol containing twice the number of carbon atoms of the single starting alcohol, or in the case of mixed starting alcohols, the sum of the number of carbon atoms in each reacting pair of alcohols. For example, ethanol can be self condensed to form n-butanol while a mixture of ethanol and n-propanol can be condensed to form n-butanol, 2-methylpentanol, n-pentanol and 2-methylbutanol. Much of the development work or improving the Guerbet reaction has been centered on the nature of the catalyst system. Thus, in U.S. Pat. No. 2,762,847 there is disclosed the use of catalyst composed of an alkali or alkaline earth metal phosphates as catalysts. In U.S. Pat. Nos. 2,971,033 and 3,479,412 there is disclosed mixtures of potassium carbonate, magnesium oxide and copper chromite and soluble compounds of metals of the platinum series respectively as catalysts for the Guerbet reaction.
Although the Guerbet reaction has been a primary focus of research in recent years, other different methods for making higher alcohols have also been investigated. Illustrative of these other methods are the so-called oxo-reaction or hydroformylation of olefins whereby carbon monoxide and hydrogen are added across the double bond in the presence of a catalyst to form the alcohol functionality and a reaction by homologation using hydrogen and carbon monoxide in the presence of a soluble cobalt compound as a catalyst to produce a C.sub.n alcohol from a C.sub.n-1 alcohol.
Notwithstanding the variety and extent of previous investigations into the synthesis of higher molecular weight alcohols from lower alcohols and olefins, there has heretofore been no commercially successful procedure for the one-step conversion of such simple and cheap starting materials such as propanol, methanol and ethanol into more valuable products such as the alcohols in the C.sub.6-12 range. Among the many reasons for the failure of the previous catalyst reactions is the inability of the catalyst formulations to withstand the elevated temperature and pressures inherent in these processes without loss of catalytic activity in a very short period of time. The present invention is directed to a novel catalyst system useful in the oxygenate condensation of low molecular weight alcohols to high molecular weight alcohols wherein the catalyst exhibits a significant improvement in lifetime and can be operated under relatively mild conditions with high selectivity and reactivity.